Experiments have been conducted with Ge and Si to define the metallurgical effects of temperature gradients in the alloying technology. These effects are defined in terms of the electrical characteristics of alloyed diodes and transistors and in terms of the physical appearance of thep‐njunction. The presence of temperature gradients during the dissolution phase of an alloy cycle results in near‐planar junctions with identical electrical characteristics on the 111, 110, and 100 alloying surfaces if the melt is hotter than the solid, and results in nonplanar junctions on all alloying surfaces if the melt is cooler than the solid. The presence of temperature gradients during the crystal growth phase of an alloy cycle results in uniform regrowth layers if the melt is hotter than the solid, and results in nonuniform regrowth layers which contain gross crystal defects if the melt is cooler than the solid. The major electrical consequences are due to the gross crystal defects and take the form of soft reverse breakdown behavior and forward lnI‐Vcharacteristics that deviate from the single‐slope model ofp‐njunction theory. It is shown that temperature gradients with the melt cooler than the solid should be avoided and that temperature gradients with the melt hotter than the solid can be used to advantage.